If You Build Bike Lanes, They Will Ride

Science has verified something that may appear obvious at first glance: The direct connection between the presence of bike lanes and the number of bike commuters. The more infrastructure exists to encourage biking, the more people bike—and the more society reaps the public health, energy, and lifestyle benefits that come with an increasing share of people-powered transportation.

Beyond the availability of bike friendly-infrastructure, other hypotheses explain why people bike more or less—whether a city is wet or dry, hot or cold, has high gas prices, is densely constructed or sprawling, is populated with young or old people. All of these variables play some role in motivating people to get on two wheels, but until now, we didn’t have a good sense of which was the most important.

A new study [PDF] of 90 of the 100 largest cities in the U.S. helps answer the question of what makes a city bicycle-friendly—and it turns out that the most important factor affecting the number of cyclists is the prevalence of bike paths.

That makes sense to me: When I lived in Washington, D.C. last year, I rode my bike to work and nearly everywhere else, despite the city’s crushing summer humidity and chilly winters. Now that I’ve moved to Los Angeles, which boasts temperate weather basically every day, I barely ride at all—the absence of road shoulders, much less real cycle paths, makes bike commuting here a rather dicey prospect.

Indeed, depending on how you judge what makes a city best for cycling, it’s often the colder ones that win out: Frozen Minneapolis is one of the best biking cities, thanks to well-built infrastructure and a bike share system. Rainy Portland continues to have the largest percentage of its population commuting by bike, a fact that should continue to shame city managers whose polities stay pleasant all year round.

Still, Portland’s 4.2 percent of commuters biking is nothing compared to Copenhagen’s 37 percent. Reaching that level of bicycle penetration in American cities would have numerous positive effects for society, and judging by this study, demands increased investment in the bike lanes that will bring cyclists out in droves.

It’s also an opportunity to kill two birds with one stone: It turns out that building bike lanes actually employs more people than projects like road resurfacing, since it is labor-intensive, not machine-reliant, business. In cities where NIMBY activists and budget cuts are raising the political cost of laying bike lanes, the employment argument is a powerful case for additional investment. on top of all the other benefits that come with bike commuting. Less traffic for folks who stay in fossil fuel vehicles is part of the argument, too.

With this research in hand, the prescription for cities is clear: Want bikes? Build lanes.